Distal Radius Fracture Fixation Plate with Ulnar Buttress

ABSTRACT

A distal volar fixation plate includes a body portion and a head portion angled upwards relative to the body portion. The head portion includes a lower surface, a central portion, a radial side and an ulnar side. The head portion defines a buttress portion extends greater distally on the ulnar side than on the radial side to support the volar lip of the lunate fossa.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 12/791,405, filedJun. 1, 2010, which is a continuation of U.S. Ser. No. 10/664,371, filedSep. 17, 2003, now issued as U.S. Pat. No. 7,857,838, which are herebyincorporated by reference herein in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates broadly to surgical implants. More particularly,this invention relates to a bone fracture fixation system for distalradius fractures.

2. State of the Art

Fracture to the metaphyseal portion of a long bone can be difficult totreat. Improper treatment can result in deformity and long-termdiscomfort.

By way of example, a Colles' fracture is a fracture resulting fromcompressive forces being placed on the distal radius, and which causesbackward or dorsal displacement of the distal fragment and radialdeviation of the hand at the wrist. Often, a Colles' fracture willresult in multiple bone fragments which are movable and out of alignmentrelative to each other. If not properly treated, such fractures mayresult in permanent wrist deformity and limited articulation of thewrist. It is therefore important to align the fracture and fixate thebones relative to each other so that proper healing may occur.

Alignment and fixation of a metaphyseal fracture (occurring at theextremity of a shaft of a long bone) are typically performed by one ofseveral methods: casting, external fixation, interosseous wiring, andplating. Casting is non-invasive, but may not be able to maintainalignment of the fracture where many bone fragments exist. Therefore, asan alternative, external fixators may be used. External fixators utilizea method known as ligamentotaxis, which provides distraction forcesacross the joint and permits the fracture to be aligned based upon thetension placed on the surrounding ligaments. However, while externalfixators can maintain the position of the wrist bones, it maynevertheless be difficult in certain fractures to first provide thebones in proper alignment. In addition, external fixators are often notsuitable for fractures resulting in multiple bone fragments.Interosseous wiring is an invasive procedure whereby screws arepositioned into the various fragments and the screws are then wiredtogether as bracing. This is a difficult and time-consuming procedure.Moreover, unless the bracing is quite complex, the fracture may not beproperly stabilized. Plating utilizes a stabilizing metal platetypically against the dorsal side of the bones, and a set of parallelpins extending from the plate into holes drilled in the bone fragmentsto provide stabilized fixation of the fragments. However, many currentlyavailable plate systems fail to provide desirable alignment andstabilization.

In particular, with a distal radius fracture the complex shape of thedistal radius, including the bulky volar rim of the lunate fossa,relatively flat volar rim of the scaphoid fossa, and volar marginalfragment from the lunate fossa should be accommodated. A fixation plateshould provide desirable alignment and stabilization of both thesubchondral bone and the articular surfaces of the distal radius.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an improvedfixation system for distal radius fractures.

It is another object of the invention to provide a distal radius volarfixation system that desirably aligns and stabilizes multiple bonefragments in a fracture to permit proper healing.

It is also an object of the invention to provide a distal radius volarplate system which provides support for articular and subchondralsurfaces.

It is an additional object of the invention to provide a distal radiusvolar plate system which accommodates the anatomical structure of themetaphysis of the distal radius.

It is a further object of the invention to provide a distal radius volarplate system which provides support without interfering with ligamentsand soft tissues near the edge of the articular surface.

In accord with these and other objects, which will be discussed indetail below, a distal radius volar fixation system is provided. Thesystem generally includes a plate intended to be positioned against thevolar side of the radius, a plurality of bone screws for securing theplate along a non-fractured portion of the radius bone, a plurality ofbone pegs sized to extend from the plate and into bone fragments at themetaphysis of a radius bone, and one or more K-wires to facilitatealignment and fixation of the plate over the bone and guide the processof application.

The plate is generally T-shaped, defining an elongate body and agenerally transverse head angled upward relative to the body, andincludes a first side which is intended to contact the bone, and asecond side opposite the first side. The body includes a plurality ofcountersunk screw holes for the extension of the bone screwstherethrough, and optionally one or more substantially smaller alignmentholes. The lower surfaces of the radial and ulnar side portions of thehead are contoured upward (in a Z direction) relative to the remainderof the head to accommodate the lunate and scaphoid processes. Anextension is provided at the head portion along the distal ulnar side ofthe head to buttress the volar lip (marginal fragment) of the lunatefossa of the radius bone, thereby providing support to maintain thewrist within the articular socket. Moreover, the contoured shapeprovides a stable shape that prevents rocking of the plate on the bone.The upper and lower surfaces are chamfered to have a reduced profilethat limits potential interface with the ligaments and soft tissue nearthe edge of the lunate fossa. The head includes a plurality of threadedpeg holes for receiving the pegs therethrough. The peg holes arearranged into a first set provided in a proximal portion of the head,and a second relatively distal set preferably provided in the taperedportion of the head.

The first set of the peg holes is substantially linearly arrangedgenerally laterally across the head. The line of pegs is preferablyslightly oblique relative to a longitudinal axis through the body of theplate. Axes through the first set of holes are preferably obliquerelative to each other, and are preferably angled relative to each otherin two dimensions such that pegs inserted therethrough are similarlyobliquely angled relative to each other. The pegs in the first set ofpeg holes provide support for the dorsal aspect of the subchondral bonefragments.

The second set of peg holes is provided relatively distal of the firstset. The holes of the second set, if more than one are provided, areslightly out of alignment but generally linearly arranged. The pegs inthe second set of peg holes provide support for the volar aspect of thesubchondral bone, behind and substantially parallel to the articularbone surface.

A distal alignment hole is provided generally between two peg holes ofthe second set of peg holes. At the upper surface of the plate, thedistal alignment hole is substantially cylindrical, while at the lowersurface, the hole is laterally oblong. One or more proximal alignmentholes of a size substantially smaller than the peg holes are providedsubstantially along a distal edge defined by a tangent line to shafts ofpegs inserted in the first set of peg holes, and facilitate temporaryfixation of the plate to the bone with K-wires. Furthermore, along thebody two longitudinally displaced alignment holes are also provided. Allof the alignment holes are sized to closely receive individual K-wires.

The plate may be used in at least two different manners. According to afirst use, the surgeon reduces a fracture and aligns the platethereover. The surgeon then drills K-wires through the proximalalignment holes to temporarily fix the orientation of the head of theplate to the distal fragment. Once the alignment is so fixed, thefracture is examined, e.g., under fluoroscopy, to determine whether theK-wires are properly aligned relative to the articular surface. As theaxes of the proximal alignment holes correspond to axes of adjacent pegholes, the fluoroscopically viewed K-wires provide an indication as towhether the pegs will be properly oriented. If the placement is correct,the K-wires maintain the position of the plate over the fracture. Thepeg holes may then be drilled with confidence that their locations andorientations are proper. If placement is not optimal, the K-wires can beremoved and the surgeon has an opportunity to relocate and/or reorientthe K-wires and drill again. Since each K-wire is of relatively smalldiameter, the bone is not significantly damaged by the drilling processand the surgeon is not committed to the initial drill location and/ororientation.

According to a second use, the plate may be used to correct ametaphyseal deformity (such as malformed fracture or congenitaldeformity). For such purposes, a K-wire is drilled into the boneparallel to the articular surface in the lateral view under fluoroscopyuntil one end of the K-wire is located within or through the bone andthe other end is free. The free end of the K-wire is guided through thedistal oblong alignment hole of the head of the plate, and the plate isslid down over the K-wire into position against the bone. The oblongalignment hole permits the plate to tilt laterally over the K-wire tosit flat on the bone, but does not permit movement of the plate over theK-wire in the anterior-posterior plane. The surgeon drills holes in thebone in alignment with the peg holes and then fixes the plate relativethe bone with pegs. The bone is then cut, and the body of the plate islevered toward the shaft of the bone to re-orient the bone. The body ofthe plate is then fixed to the shaft to correct the anatomical defect.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a radial side elevation of a right-hand volar plate accordingto the invention, shown with pegs coupled thereto;

FIG. 2 is an ulnar side elevation of a right-hand volar plate accordingto the invention, shown with pegs coupled thereto;

FIG. 3 is top view of a right-hand volar plate according to theinvention, shown with pegs and screws;

FIG. 4 is bottom view of a right-hand volar plate according to theinvention, shown with pegs coupled thereto;

FIG. 5 is a perspective view of a right-hand volar plate according tothe invention, shown with pegs coupled thereto and K-wires extendingthrough body and proximal head alignment holes;

FIG. 6 is a front end view of a right-hand volar plate according to theinvention, shown with pegs coupled thereto and K-wires extending throughalignment holes; and

FIGS. 7 through 12 illustrate a method of performing an osteotomy of thedistal radius according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIGS. 1 through 6, a fracture fixation system 100according to the invention is shown. The system 100 is particularlyadapted for aligning and stabilizing multiple bone fragments in adorsally displaced distal radius fracture (or Colles' fracture). Thesystem 100 generally includes a substantially rigid T-shaped plate 102,commonly called a volar plate, bone screws 104 (FIG. 3), pegs 106, 108,and K-wires 110 (FIGS. 5 and 6). Pegs 106 have a threaded head and anon-threaded shaft, and pegs 108 have both a threaded head and athreaded shaft. Either pegs 106 or 108, or a combination thereof may beused at the discretion of the surgeon. Exemplar pegs are described inmore detail in U.S. Pat. No. 6,364,882, which is hereby incorporated byreference herein in its entirety.

The volar plate 102 shown in the figures is a right-hand plate intendedto be positioned against the volar side of a fractured radius bone ofthe right arm. It is appreciated that a left-hand volar plate issubstantially a mirror image of the plate shown and now described. TheT-shaped plate 102 defines an elongate body 116, and a head 118 angledupward (in the Z-direction) relative to the head. The angle a betweenthe head 118 and the body 116 is preferably approximately 25°. The head118 includes a distal buttress 120 (i.e., the portion of the head distala first set of peg holes 134, discussed below). The plate 102 has athickness of preferably approximately 0.1 inch, and is preferably madefrom a titanium alloy, such as Ti-6Al-4V.

Referring to FIG. 4, the body 116 includes four preferably countersunkscrew holes 124, 125, 126, 127 for the extension of bone screws 104therethrough (FIG. 2). One of the screw holes, 127, is preferablygenerally oval in shape permitting longitudinal movement of the plate102 relative to the shaft of a bone screw when the screw is not tightlyclamped against the plate.

Referring to FIGS. 3 and 4, according to one preferred aspect of theplate 102, the head portion 118 includes a first set of threaded pegholes 134 (for placement of pegs 106 and/or 108 therein) and a secondset of threaded peg holes 138 (for placement of pegs 106 and/or 108therein). The peg holes 134 of the first set are arranged substantiallyparallel to a line L₁ that is preferably slightly skewed (e.g., by5°-10°) relative to a perpendicular P to the axis A of the body portion116. Axes through the first set of peg holes (indicated by the pegs 106extending therethrough) are preferably oblique relative to each other,and are preferably angled relative to each other in two dimensions,generally as described in commonly-owned U.S. Pat. No. 6,364,882, whichis hereby incorporated by reference herein in its entirety. Thisorientation of the pegs operates to stabilize and secure the head 118 ofthe plate 102 on the bone even where such pegs 106 do not have threadedshafts.

The second set of peg holes 138 is provided relatively distal of thefirst set of peg holes 134 and is most preferably primarily located inthe buttress 120. Each of the peg holes 138 preferably defines an axisthat is oblique relative to the other of peg holes 136 and 138. Thus,each and every peg 106, 108 when positioned within respective peg holes134, 138 defines a distinct axis relative to the other pegs. Moreover,the axes of the peg holes 138 are preferably oriented relative to theaxes of peg holes 134 such that pegs 106, 108 within peg holes 138extend (or define axes which extend) between pegs (or axes thereof)within peg holes 134 in an interleaved manner.

Referring specifically to FIGS. 1, 2, 5 and 6, according to anotherpreferred aspect of the plate 102, in order to approximate the anatomyfor ideal fracture support and maintain a low profile, the upper andlower surfaces 140, 142, respectively of the buttress 120 are chamfered,with the chamfer of the lower surface 142 being contoured for theanatomical structure that it will overlie. In particular, the lowersurface 142 at an ulnar-side portion 144 of the head portion 118 iscontoured upward (in a Z direction) both distally and laterally toaccommodate the bulky volar rim of the lunate fossa, and the lowersurface 142 at a radial side portion 146 of the head 118 is contouredupward laterally relative to the remainder of the head to accommodate aprominence at the radial aspect of the bone, as indicated by thevisibility of these lower surfaces in the side views of FIGS. 1 and 2and head-on view of FIG. 6. The contoured shape (with generally threedefined planes) provides a stable shape that prevents rocking of theplate on the bone. In addition, the upper and lower surfaces 140, 142are chamfered to have a reduced profile that limits potential interfacewith the ligaments and soft tissue near the edge of the articularsurface. A distal extension 148 is also provided at the ulnar sideportion 146 to further buttress the volar lip (volar marginal fragmentof the lunate fossa) of the articular socket of the radius bone, therebyproviding support to maintain the wrist within the articular socket.

Referring specifically to FIGS. 3 and 4, according to a furtherpreferred aspect of the invention, the plate 102 is provided with bodyalignment holes 150, proximal head alignment holes 152 a, 152 b, 152 c(generally 152), and a distal head alignment hole 154, each sized toclosely accept standard Kirschner wires (K-wires), e.g., 0.7-1.2 mm indiameter. All the alignment holes 150, 152, 154 are substantiallysmaller in diameter (e.g., by thirty to fifty percent) than the shaftsof screws 104 (approximately 3.15 mm in diameter) and the shafts of pegs106, 108 (approximately 2.25 mm in diameter). The body alignment holes150 are longitudinally displaced along the body portion 116 and providedat an oblique angle (preferably approximately 70°, as shown in FIG. 5)relative to the lower surface 158 of the body portion 116. The proximalhead alignment holes 152 alternate with the peg holes 134. A tangentline H to the distalmost points of the head alignment holes 152 ispreferably substantially coincident or closely parallel with a linetangent to points on the circumferences of the shafts of pegs 106inserted through holes 134 adjacent the head portion 118 of the plate102. With respect to the proximal head alignment holes, it isappreciated that a shaft 106 a of a peg is generally smaller in diameterthan a head 106 b of a peg (FIG. 6). Thus, a line tangent to the pegholes 134 (each sized for receiving the head 106 b of peg 106) will beclosely located, but parallel, to a line tangent to a distalmost pointon the respective alignment hole 152. Nevertheless, for purposes of theclaims, both (i) a tangent line which is preferably substantiallycoincident with a line tangent to points on the circumferences of theshafts of pegs and (ii) a tangent line to a set of peg holes shall beconsidered to be “substantially coincident” with a line tangent to adistalmost point of an alignment hole 152. Axes through alignment holes152 preferably generally approximate (within, e.g., 3°) the angle of anaxis of an adjacent peg hole 134. Distal head alignment hole 154 isprovided between the central and radial-side peg holes 138, and has acircular upper opening, and a laterally oblong lower opening, as shownbest in FIG. 6.

The plate may be used in at least two different applications: fracturefixation and correction of a metaphyseal deformity. In eitherapplication, an incision is first made over the distal radius, and thepronator quadratus is reflected from its radial insertion exposing theentire distal radius ulnarly to the distal radioulnar joint. Forfracture fixation, the surgeon reduces the fracture and aligns the plate102 thereover. The surgeon then drills preferably two K-wires 110through respective body alignment holes 150, and one or more K-wiresthrough selected proximal head alignment holes 152 at the location atwhich the surgeon believes the pegs 106, 108 should be placed based onanatomical landmarks and/or fluoroscopic guidance. The K-wirestemporarily fix the orientation of the plate to the distal fragment.While the fixation is temporary, it is relatively secure in view of thefact that the body alignment holes 150, proximal head alignment holes152, and K-wires 110 therethrough are angled in different orientationsrelative to the lower surface of the plate. Once the alignment is sofixed, the fracture is examined, e.g., under fluoroscopy, to determinewhether the K-wires 110 are properly aligned relative to the articularsurface. As the axes of the proximal head alignment holes 152 correspondto axes of the adjacent peg holes 134, the fluoroscopically viewedK-wires 110 provide an indication as to whether the pegs 106, 108 willbe properly oriented. If the placement is correct, the K-wires 110maintain the position of the plate 102 over the fracture while holes inthe bone are drilled through the screw holes 124, 125, 126, 127 for thescrews 104 and peg holes 134, 138 for pegs 106, 108, with confidencethat the locations and orientation of the screws and pegs insertedtherein are anatomically appropriate. The K-wires can then be removed.

If fluoroscopic examination indicates that placement of the K-wires 110is not optimal, the K-wires can be removed and the surgeon has anopportunity to relocate and/or reorient the K-wires and drill again.Since each K-wire is of relatively small diameter, the bone is notsignificantly damaged by the drilling process and the surgeon is notcommitted to the initial drill location and/or orientation.

The pegs 106 within peg holes 138 define projections that providesupport at the volar aspect behind the articular surface of the bonesurface. The sets of pegs 106, 108 through peg holes 134, 138 preferablylaterally alternate to provide tangential cradling of the subchondralbone. A preferred degree of subchondral support is provided with fourpeg holes 134 (and associated pegs) through the proximal portion of thehead 118 of the plate, and three peg holes 138 (and associated pegs)through the distal portion of the head 118. The fracture fixation systemthereby defines a framework which substantially tangentially supportsthe bone fragments in their proper orientation. In accord with analternate less preferred embodiment, suitable support may also beprovided where the pegs 106 and 108 are parallel to each other or inanother relative orientation or with fewer peg holes and/or pegs.

According to a second use, the plate may be used to correct ametaphyseal deformity 200 (such as malformed fracture or congenitaldeformity), as shown in FIG. 7. For such purposes, a K-wire 110 isdrilled into the bone parallel to the articular surface S in the lateralview under fluoroscopy (FIG. 8). The free end of the K-wire 110 isguided through the oblong distal head alignment hole 154, and the plate102 is slid down over the K-wire into position against the bone (FIG.9). The oblong alignment hole 154 permits the plate 102 to tiltlaterally over the K-wire 110 to sit flat on the bone, but does notpermit tilting of plate relative to the K-wire in the anterior-posteriorplane. Once the plate 102 is seated against the bone, the surgeon drillsholes in the bone in alignment with the peg holes 134, 138 (FIG. 3) andthen fixes the plate relative the bone with pegs 106, 108 (FIG. 10). TheK-wire 110 is removed. The bone is then saw cut at 202 proximal thelocation of the head 118 of the plate 102 (FIG. 11), and the body 116 ofthe plate is levered toward the proximal diaphyseal bone 204, creatingan open wedge 206 at the deformity (FIG. 12). When the body 116 of theplate 102 is in contact and longitudinal alignment with the diaphysis ofthe bone, the bone distal of the cut has been repositioned into theanatomically correct orientation relative to the shaft of the bone. Thebody 116 of the plate 102 is then secured to the bone with screws 104.Post-operatively, the open wedge in the bone heals resulting in ananatomically correct distal radius.

While fixed single-angle pegs have been disclosed for use with the plate(i.e., the pegs may be fixed in respective threaded peg holes 134, 136only coaxial with an axis defined by the respective peg holes), it isappreciated that an articulating peg system, such as that disclosed inco-owned U.S. Pat. No. 6,440,135 or co-owned and co-pending U.S. Ser.No. 10/159,612, both of which are hereby incorporated by referenceherein in their entireties, may also be used. In such articulating pegsystems, the peg holes and pegs are structurally adapted such thatindividual pegs may be fixed at any angle within a range of angles. Inaddition, while less preferable, one or both sets of the pegs may bereplaced by preferably blunt tines which are integrated into the platesuch that the plate and tines are unitary in construct. Similarly, otherelongate projections may be coupled to the plate to define the desiredsupport.

There have been described and illustrated herein embodiments of afixation plate, and particularly plates for fixation of distal radiusfractures, as well as a method of aligning and stabilizing a distalradius fracture and performing an osteotomy. While particularembodiments of the invention have been described, it is not intendedthat the invention be limited thereto, as it is intended that theinvention be as broad in scope as the art will allow and that thespecification be read likewise. Thus, while particular materials,dimensions, and relative angles for particular elements of the systemhave been disclosed, it will be appreciated that other materials,dimensions, and relative angles may be used as well. In addition, whilea particular number of screw holes in the volar plate and bone screwshave been described, it will be understood another number of screw holesand screws may be provided. Further, fewer screws than the number ofscrew holes may be used to secure to the plate to the bone. Also, feweror more peg holes and bone pegs may be used, preferably such that atleast two pegs angled in two dimensions relative to each other areprovided. In addition, while a particular preferred angle between thehead and body has been disclosed, other angles can also be used. It willtherefore be appreciated by those skilled in the art that yet othermodifications could be made to the provided invention without deviatingfrom its spirit and scope.

1.-20. (canceled)
 21. A fixation plate for fixation of a fracture at thedistal radius, the distal radius having a volar surface, a dorsalsurface, an ulnar side closer to an ulna, and a radial side opposite theulnar side, the distal radius bone having a lunate fossa with a volarlip, said fixation plate for use with a plurality of fasteners that eachhave a fastener head portion at which the fasteners are coupled to saidplate and a fastener shaft portion that can extend into the distalradius, said fixation plate comprising: a substantially rigid platesized to accommodate the anatomy of the volar surface of the distalradius, said plate having a proximally extending body portion and a headportion wider than said body portion, each of said body and headportions having a bone contacting surface, and when said bone contactingsurface of said body portion is positioned on a horizontal plate, saidhead portion is angled upward with respect to said plane, said platedefining a first set of holes for receiving the fasteners in said headportion of said plate, and a second set of holes for receiving thefasteners in said body portion, said head portion having a radial sidefor placement on the volar surface at the radial side of the distalradius, and an ulnar side for placement on the volar surface at theulnar side of the distal radius, wherein when said head portion ispositioned on the volar surface of the distal radius, said head portionextends distally a greater distance on said ulnar side of said headportion than on said radial side of said head portion to support thevolar lip of the lunate fossa of the distal radius.
 22. A fixation plateaccording to claim 21, wherein: said head portion includes a distalextension on said ulnar side to buttress the volar lip of the lunatefossa, and said first set of holes are located proximal of said distalextension.
 23. A fixation plate according to claim 21, wherein: saiddistal extension tapers to a non-linear distal edge.
 24. A fixationplate according to claim 21, wherein: each hole of said first set ofholes includes a threaded portion.
 25. A fixation plate according toclaim 21, wherein: said first set of holes includes at least four holes.26. A fixation plate according to claim 21, wherein: said first set ofholes are structurally adapted to allow each of the fasteners to beconstrained in a fixed angle relationship relative to said plate.
 27. Afixation plate according to claim 26, wherein: said plurality of holesare threaded.
 28. A fixation plate according to claim 21, wherein: saidbone contacting surface of said head portion is contoured to definethree planes of contact against the volar surface of the distal radius.29. A fixation plate for fixation of a fracture at the distal radius,the distal radius having a volar surface, a dorsal surface, an ulnarside closer to an ulna, and a radial side opposite the ulnar side, thedistal radius bone having a lunate fossa with a volar lip, said fixationplate for use with a plurality of fasteners, said fixation platecomprising: a substantially rigid plate sized to accommodate the anatomyof the volar surface of the distal radius, said plate having aproximally extending body portion and a head portion oriented at one endof the body portion extending wider than said body portion, each of saidbody portion and head portion having a bone contacting surface, and whensaid bone contacting surface of said body portion is positioned on ahorizontal plate, said head portion is angled upward with respect tosaid plane, said plate defining a plurality of holes for receiving thefasteners, said head portion including a radial side for placement onthe volar surface at the radial side of the distal radius, and an ulnarside for placement on the volar surface at the ulnar side of the distalradius, said ulnar side having a buttress portion, wherein when saidhead portion is positioned on the volar surface of the distal radiussaid buttress portion extends distally a greater distance on said ulnarside than said radial side of said plate extends along the radial sideof the radius bone, such that said plate provides support to the volarlip of the lunate fossa of the distal radius.
 30. A fixation plateaccording to claim 29, wherein: said head portion includes a centralportion situated between said ulnar side and said radial side, said bonecontacting surface of said head portion at said ulnar side is elevatedupward relative to said bone contacting surface at said central portion,and said bone contacting surface of said head portion at said radialside is elevated upward relative to said bone contacting surface at saidcentral portion.
 31. A fixation plate according to claim 29, wherein:said buttress portion includes at least one hole of a second set ofholes.
 32. A fixation plate according to claim 29, wherein: said headportion tapers toward a distal edge.
 33. A fixation plate according toclaim 29, wherein: said buttress portion tapers in thickness in a distaldirection.
 34. A fixation plate according to claim 29, wherein: a firstset of said plurality of holes extends in a generally medial-lateraldirection.
 35. A fixation plate according to claim 34, wherein: saidbuttress portion is located distal of said first set of holes.
 36. Afixation plate according to claim 29, wherein: said plurality of holesare structurally adapted to allow each of the fasteners to beconstrained in a fixed angle relationship relative to said plate.
 37. Afixation plate according to claim 36, wherein: said plurality of holesare threaded.
 38. A fixation plate according to claim 29, wherein: saidbone contacting surface of said head portion is contoured to definethree planes of contact against the volar surface of the distal radius.